Low-frequency bandgap characteristics of a new cement-based locally resonant phononic crystals composite material with multiple oscillators

Locally resonant phononic crystals (LRPCs) materials have elastic wave bandgap characteristics and have good application prospects in many fields. However, the traditional LRPCs materials have the shortcomings of narrow bandgap width and small effective attenuation of elastic waves within the bandgap range, which is limited in practical engineering applications. To solve the problem of narrow bandgap width of traditional cement-based LRPCs materials, this paper proposes a new cement-based LRPCs composite material with multiple oscillators based on local resonance theory. Firstly, the band structure of the multiple oscillators cement-based LRPCs composite material is calculated by finite element method, the bandgap mechanism is analyzed, and the bandgap width widening method is discussed. Secondly, the frequency response function is calculated to evaluate its attenuation effect within the bandgap frequency range. Finally, a spring-mass system equivalent model and an effective mass model of the multiple oscillators cement-based LRPCs are established to solve the bandgap range and the effective mass expression. The bandgap range calculated by theory agrees well with the finite element calculation. The results show that the multiple oscillators cement-based LRPCs composite material open two lowfrequency bandgaps in the frequency range of 0-200 Hz, and the attenuation values within the bandgap frequency range are mostly above 15 dB. Compared with the corresponding single oscillator cement-based LRPCs, the open bandgap range is wider, the bandgap width is significantly increased, and the overall attenuation effect is better. The relevant results of this paper provide a specific reference for designing the structure of multiple oscillators cement-based LRPCs composite materials, widening the bandgap width of LRPCs materials, and materials design in the field of low-frequency vibration control.